Ably has been designed from the ground up to cope with the following types of unexpected failures:

Unexpected server failures: all data is stored in at least three data centres, with two of those data centres required to be in different regions. A failure of a single server or even an entire region will have no impact on the reliability of our service, any message received will still be delivered successfully. Find out more about message durability and QoS guarantees

Internal network partitioning: if a region or group of servers become isolated from the rest of the global network of servers, using our consensus algorithm, those servers will be removed from the cluster and the service will continue all operations. Find our more about our self healing cluster

Network, routing issues and DNS failures: if a single client is unable to access the closest data centre due to DNS failures, network outages and or routing issues, our client libraries will route around these issues by connecting to an alternative data centre. Find out more about our proprietary intelligent routing systems

We offer 100% uptime SLA on the Ably realtime service because we know we have built the system to handle server hardware and software failures without any loss of data and service reliability. As such, server crashes are considered normal for day to day operation and will have no impact on the service.